Proposed is a technology in which the number of times that a user gazes at a commodity from a start to an end of a buying behavior by the user is counted, and a commodity the number of times for which is not less than a given number of times is estimated as a gazed commodity. Herein, it is determined that the user has certain interests in all the commodities the number of gazed times for which is not less than the given number of times, or vacillates whether to purchase the commodities.
Examples of the related art include Japanese Laid-open Patent Publication No. 2009-42956.